海上稠油入井液伤害机理及低伤害入井液体系研究

Study on Damage Mechanism of Injected Fluid in Offshore Heavy Oil Reservoirs and Development of Low Damage Injected Fluid System

针对埕岛油田海上稠油油藏入井液进入地层易造成地层伤害,分析了海上稠油入井液伤害机理并研究了适合海上稠油油藏低伤害入井液体系。结果表明:海上稠油粘度对温度十分敏感,低温入井液易造成冷伤害。同时携砂液与海上稠油易发生乳化作用,导致入井液返排困难,造成地层伤害;且胍胶携砂液比清洁携砂液的伤害更大。在现有入井液体系的基础上研发出低伤害入井液体系:0.4%破乳剂+2%防膨缩膨剂+4%原油流动改善剂GS,通过岩心伤害评价得出该体系的渗透率伤害率小于15%。

Aiming at the problem of formation damage caused by injected fluids in Chengdao offshore heavy oil reservoir, the damage mechanism of injected fluid was analyzed, and a low damage injected fluid system for offshore heavy oil reservoirs was developed. The results show that the viscosity of offshore heavy oil is very sensitive to temperature, low temperature injected fluid can easily cause the cold damage. The emulsification between the sand-carrying fluid and heavy oil can increase the difficulty of the flowback of injected fluid, resulting in formation damage. The sand-carrying fluid prepared by guanidine glue is more harmful than clean sand-carrying fluid. Based on the existing injected fluid system, a low damage injected fluid system has been developed, its formulation is 0.4% demulsifier＋2% anti-swelling agent ＋4% crude oil flow improver GS. The evaluation of core damage shows that the damage rate of the system is less than 15%.